Bacterial ribosomes contain 3 different RNA molecules and about 50 different protein components. We wish to understand the complex series of events which originates in the transcription of the more than 60 genes and culminates in the formation of the complex, yet specific, structure of the organelle. More specifically, we wish to identify all the structural genes for ribosomal components (both ribosomal proteins and rRNAs), elucidate their organization, including their promoters and any other regulatory genes needed for expression, and understand how cells regulate the expression of ribosomal genes. In addition, we wish to learn how synthesis of ribosomal RNA and r-proteins is coordinated and how ribosome assembly takes place from these components in a controlled way in vivo. Eventually, we would like to reproduce all the in vivo assembly events in the test tube and to study in vitro, factors regulating the organelle biogenesis. Finally, we wish to learn how the regulatory systems for ribosome biogenesis are interconnected with other major regulatory systems, such as those governing the synthesis of transcriptional machinery or those concerned with DNA replication and cell division, and how they function as part of a more complex system governing overall regulation of cellular growth.